package cn.edu.zsc.blms.service.impl.array;

import cn.edu.zsc.blms.App;
import cn.edu.zsc.blms.domain.BaseEntity;
import cn.edu.zsc.blms.exception.EntityNotExistException;


public abstract class BaseServiceImpl {
    protected final BaseEntity[] DATA;

    protected int idCounter;
    public BaseServiceImpl(){
        DATA = new BaseEntity[100];
}

    /** 获取用户输入的有效ID值，返回-1表示用户输入的ID值是无效的*/
    protected BaseEntity getOne() throws EntityNotExistException{
        BaseEntity entity;
        try{
            int id=Integer.parseInt(App.input.nextLine());
            if(id>=idCounter||DATA[id]==null){
                throw new EntityNotExistException();
            }
            entity=DATA[id];
        }catch(NumberFormatException e){
            throw new EntityNotExistException("ID为整数，请输入整数值");
        }
        return entity;
    }

}